Method of manufacturing a fuel inlet

Abstract

A method of manufacturing a fuel inlet having an improved anti-rust property. As material for an inlet pipe 2 and a breather tube 4, stainless pipes are used. A pipe expanding process in which an end portion of the inlet pipe 2 is enlarged in diameter to form a filling part 6 , a screw-thread forming process in which a helical groove 12 is formed on a periphery of the filling part 6 , a welding process in which the breather tube 4 is welded to the inlet pipe 2 , and a coating process in which a cationic electrodeposition coating is applied to a fuel inlet 1 after the welding process are performed in turn, thereby obtaining the fuel inlet 1 having an improved anti-rust property.

What is claimed is:  
     
       1. A method of manufacturing a fuel inlet, the fuel inlet comprising an inlet pipe for conveying fuel into a fuel tank and a breather tube for venting air from the fuel tank toward an end of the inlet pipe when the fuel is filled into the fuel tank, the method comprising the steps of: 
       providing a first stainless pipe for manufacturing the inlet pipe and a second stainless pipe for forming the breather tube;  
       expanding an end portion of the inlet pipe to form a filling part having a larger diameter than a remainder of the inlet pipe;  
       forming a helical groove on a peripheral wall of the filling part to produce a screw-thread in the filling part;  
       welding the breather tube to the inlet pipe; and  
       applying a cationic electrodeposition coating to the fuel inlet.  
     
     
       2. The method of manufacturing a fuel inlet according to  claim 1 , further comprising the step of providing the first and second stainless pipes made of a stainless material SUS436. 
     
     
       3. The method of manufacturing a fuel inlet according to  claim 1 , further comprising the step of welding an open attachment end of the breather tube to a peripheral wall of the inlet pipe by means of projection welding. 
     
     
       4. The method of manufacturing a fuel inlet according to  claim 1 , further comprising the step of forming the helical groove by inserting a core bar on which a groove is formed into the filling part, and a roller is moved along the groove, while being pressed against the peripheral wall of the filling part, thereby forming the helical groove. 
     
     
       5. The method of manufacturing a fuel inlet according to  claim 1 , further comprising the step of forming the larger diameter of the filling part offset from a diameter of the remainder of the pipe during the pipe expanding step. 
     
     
       6. The method of manufacturing a fuel inlet according to  claim 5 , further comprising the step of flaring an edge portion of the filling part of the inlet pipe to fold back an open end of the filling part of the fuel inlet. 
     
     
       7. The method of manufacturing a fuel inlet according to  claim 3 , further comprising the step of forming a seat as a first flat portion in the peripheral wall of the inlet pipe  2  by press working a portion of the inlet pipe. 
     
     
       8. The method of manufacturing a fuel inlet according to  claim 7 , further comprising the step of forming a second flat portion in the peripheral wall on an opposite side of the inlet pipe to that of the seat in order that the inlet pipe can be easily supported for projection welding of the breather tube in the seat. 
     
     
       9. The method of manufacturing a fuel inlet according to  claim 8 , further comprising the steps of inserting a substantially rectangular shaped electrode inside the inlet pipe to contact the first and second flat portions of the seat formed therein and positioning a second electrode circumscribing the open attachment end of the breather tube on an outer side of the flat portion of the seat and applying current between the electrodes to weld the breather tube to the seat. 
     
     
       10. The method of manufacturing a fuel inlet according to  claim 4 , further comprising the steps of providing a rough and a fine roller wherein the rough roller is initially moved along the groove and subsequently followed by the fine roller being moved along the groove to form the helical groove in the peripheral wall of the filling part. 
     
     
       11. The method of manufacturing a fuel inlet according to  claim 10 , further comprising the steps of supporting the rough and fine rollers on a rotator and circumferentially rotating the rotator about the inlet pipe which is held in a substantially fixed position with respect to the rotator. 
     
     
       12. The method of manufacturing a fuel inlet according to  claim 11 , further comprising the step of also providing the rotator with an axial movement substantially along a longitudinal axis defined by the inlet pipe and radially moving the rough and fine rollers to press against the peripheral wall of the inlet pipe to form the helical groove in the filling part of the inlet pipe. 
     
     
       13. The method of manufacturing a fuel inlet according to  claim 1 , further comprising the step of electrodepositing a coating material chosen from the group of an acrylic coating, an alkyd coating, a urethane coating, and an epoxy coating, all of which are provided in the form of one of a cationic aqueous solution and an emulsion. 
     
     
       14. A method of manufacturing a fuel inlet, the fuel inlet comprising an inlet pipe for conveying fuel into a fuel tank and a breather tube for venting air from the fuel tank toward an end of the inlet pipe when the fuel is filled into the fuel tank, the method comprising the steps of: 
       providing a first stainless pipe for manufacturing the inlet pipe and a second stainless pipe for forming the breather tube;  
       expanding an open end of the inlet pipe to form a filling part having a larger diameter than a remainder of the inlet pipe and forming the larger diameter of the filling part offset from a diameter of the remainder of the pipe;  
       flaring an edge of the filling part to fold back the open end of the filling part of the fuel inlet;  
       forming a helical groove on an outer surface of a peripheral wall of the filling part to produce a screw-thread on an inner surface of the peripheral wall of the filling part;  
       welding the breather tube to the inlet pipe; and  
       applying a cationic electrodeposition coating to the fuel inlet.  
     
     
       15. The method of manufacturing a fuel inlet according to  claim 14 , further comprising the step of forming the helical groove by inserting a core bar on which a groove is formed into the filling part, and at least a first roller is pressed against the outer peripheral surface of the filling part and follows along the groove of the core bar thereby forming the helical groove in the filling part. 
     
     
       16. The method of manufacturing a fuel inlet according to  claim 15 , further comprising the steps of providing a rough and a fine roller wherein the rough roller is initially moved along the groove and subsequently followed by the fine roller being moved along the groove to form the helical groove in the peripheral wall of the filling part. 
     
     
       17. The method of manufacturing a fuel inlet according to  claim 16 , further comprising the steps of supporting the rough and fine rollers on a rotator and circumferentially rotating the rotator about the inlet pipe which is held in a substantially fixed position with respect to the rotator. 
     
     
       18. The method of manufacturing a fuel inlet according to  claim 17 , further comprising the step of also providing the rotator with an axial movement substantially along a longitudinal axis defined by the inlet pipe and radially moving the rough and fine rollers to press against the peripheral wall of the inlet pipe to form the helical groove in the filling part of the inlet pipe. 
     
     
       19. A method of manufacturing a fuel inlet, the fuel inlet comprising an inlet pipe for conveying fuel into a fuel tank and a breather tube for venting air from the fuel tank toward an end of the inlet pipe when the fuel is filled into the fuel tank, the method comprising the steps of: 
       providing a first stainless pipe for manufacturing the inlet pipe and a second stainless pipe for forming the breather tube;  
       expanding an open end of the inlet pipe to form a filling part having a larger diameter than a remainder of the inlet pipe and forming the larger diameter of the filling part offset from a diameter of the remainder of the pipe;  
       flaring an edge of the filling part to fold back the open end of the filling part of the fuel inlet;  
       forming a helical groove on an outer surface of the peripheral wall of the filling part to produce a screw-thread on an inner surface of the peripheral wall of the filling part by inserting a core bar on which a groove is formed into the filling part, and a rough and a fine roller are sequentially pressed against the outer surface of the peripheral wall and follow along the groove of the core bar thereby forming the helical groove in the peripheral wall of the filling part,  
       welding the breather tube to the inlet pipe; and  
       applying a cationic electrodeposition coating to the fuel inlet.